This project proposes to study the incidence, morphology and orientation of cilia from articular chondrocytes from normal mice, dogs and horses and to see if incidence, morphology and orientation of chondrocytic cilia is altered in the arthritic state. Thus far we have demonstrated that all normal articular chondrocytes have 1 cilium regardless of species, age, or region of the joint. Furthermore, we have demonstrated that chondrocytic cilia are highly oriented in 3-dimensional space. Six dogs were made arthritic by experimentally severing the cranial cruciate ligament. This arthritic cartilage plus arthritic cartilage from spontaneously occurring cases of degenerative joint disease has been collected and in this coming year the chondrocytic cilia in this cartilage will be studied for incidence, morphology and orientation.